The Battle of Serroco was an engagement during the Mandalorian Wars between the Galactic Republic and the Mandalorian Neo-Crusaders in the year3963 BBY. Anticipating that the Mandalorians would move on the muddy planetSerroco in the Expansion Region, Republic NavyAdmiralSaul Karath assembled a battle group and moved to defend the world. The Navy decide to place their camps next to Serroco's Stereb cities, betting that the Mandalorians would not want to risk wrecking the cities and depriving themselves of the loot to be found within—they were wrong. When the Mandalorians arrived, their chief, Mandalore the Ultimate, deemed the Republic tactic "without honor" and unleashed a barrage of nuclear bombs that destroyed the Stereb cities. With Serroco devastated, Karath marshaled his remaining forces and retreated, hoping to link up with reinforcements further away from shattered Serroco. The Mandalorians pursued, finally catching up to Karath's flagship, the Courageous, in deep space. The Courageous was severely damaged and boarded, and Admiral Karath barely escaped with his life. The destruction of Serroco was decried as an atrocity and a crime by the Republic, and Serroco's memory became a rallying cry for the Republic throughout the rest of the war.

The group was headed by the Inexpugnable-class tactical command ship[11]Courageous, Karath's flagship. The battle group set down camps near Serroco's Stereb cities, which housed a great number of naval personnel alongside freelance tradespeople who tagged along, offering food and other services. Notably, Serroco's Camp Three featured the extremely popular Little Bivoli eatery. Unbeknownst to the Republic Navy, the Little Bivoli was run by two of the Republic's most wanted fugitives—Zayne Carrick, a former JediPadawan accused of murdering his whole class on Taris, and his Snivvian "accomplice" Marn Hierogryph. By setting their camps so close to the cities, the Republic was hoping that they would be better able to protect them, counting on the idea that the Mandalorians would not want to destroy potentially valuable loot in the cities. In addition to the Republic Army troopers[4] and Navy shuttles and other craft at the camps, Battle Group Serroco surrounded Serroco with a blockade of vessels, including Hammerhead-class cruisers, similarly-designed starships, Foray-class blockade runners and a number of Aurek-class strikefighters.[3] However, Carrick had a vision—the former Jedi Padawan, while on a break from his duties at the Little Bivoli, foresaw that Mandalore the Ultimate would order the cities destroyed out of disgust for the Republic's tactics. Horrified, Carrick resolved to warn Admiral Karath and attempt to avert disaster.[4]

Carrick hitched a ride up to the Courageous on Republic pilotCarth Onasi's[3]short-haul craft,[6] the Deadweight, but upon reaching the bridge was immediately recognized as a wanted fugitive. Karath thought that Carrick was a Mandalorian spy, and refused to heed his warnings. Expecting the Mandalorians to arrive any minute, Karath decided to keep Carrick on the bridge of the Courageous, to show him what the Republic would do to Carrick's "friends"—sure enough, a Mandalorian battle group featuring a Kandosii-type dreadnaught and several Jehavey'ir-type assault ships emerged from hyperspace. It was small enough of a force to draw Karath's curiosity, as did their holding position at the edge of the Republic force's weapons perimeter. Without further ado, the Mandalorian ships launched a number of nuclear bombs that appeared to be heading for the Republic fleet. As Karath prepared countermeasures, the missiles suddenly changed course and angled around the ships—they were never aimed at the fleet. Just as Carrick had foreseen, the missiles hit the planet's surface, dealing heavy damage to Serroco's Human settlements[3] and turning the Stereb cities into glass craters.[12]

With the Republic force on Serroco decimated by the bombs destroying their camps—their missile-defense systems were not active, and thus only eight ships on the surface were able to make a getaway—Admiral Karath was left with no choice but to retreat and find a place to make a stand.[3] With the Courageous group on the run, the Mandalorians pursued Karath and his forces through the lanes between Serroco and[13] the banking world of[14]Telerath. Karath was hoping to make it to the planet Myrkr or the Ryyk Nebula, where he could merge his forces with the Tremendousbattle group in the region, but faced major difficulties. Karath had sworn that he would not allow the Mandalorians to take any of the ships in his flotilla without a fight, and the Courageous saw plenty of action to this end.[13] The Mandalorians finally caught up to the Courageous in deep space, severely damaging the Courageous and boarding the listing vessel. Karath, Onasi, and CommanderDallan Morvis were still alive, and made the decision that they had to scuttle the vessel. Faced with Neo-Crusader Shock Troopers pouring into the ship, the three retreated from the bridge under heavy fire, with Onasi narrowly saving Admiral Karath from a direct attack.[7]

With Mandalorian troopers on three levels, Karath, Onasi and Morvis gathered several soldiers and made their way into the ship's brig, hoping to find a suitable place to make a stand. After barricading the door, they went straight for the prison cells, where the still-captive Zayne Carrick had been meditating—as the Mandalorians drew nearer, Carrick rose from his spot to reveal that he had used the Force to gradually loosen bolts in the wall behind him, opening a passage from his cell to the ship's empty cargo bay. Onasi was able to fly Karath, Morvis, Carrick and several troopers out of the fray in the Deadweight, evading Mandalorian pursuit when the ship was noticed leaving the bay.[7] With the loss of the Courageous, the entirety of the Serroco battle group was lost.[8]

Saul Karath and Mandalore the Ultimate face off, with the Mandalore holding his axe made of the remains of the Courageous

After narrowly escaping death on the Courageous, Admiral Saul Karath and the passengers of the Deadweight were roped into a scheme by Arkoh Adasca, head of the medical corporation Adascorp, to establish himself as a major galactic power by offering either the Republic or the Mandalorians the services of the massive and deadly creatures known as the exogorths. They came face-to-face with Mandalore the Ultimate himself in the process, and in the ensuing chaos Adasca was killed, Carrick escaped custody, and Karath, Morvis and Onasi were able to slip away.[2] Admiral Karath limped back to the Republic capital of Coruscant, and immediately submitted his resignation to the Admiral of the Fleet, who refused to accept it and instead publicly praised Karath for his performance.[5] Having claimed victory at Serroco, the Mandalorians moved Coreward to Nouane, another world that would end up being ravaged by the warrior clans.[15] Although Serroco was severely damaged as a result of the Mandalorian attack, Carth Onasi was able to save many Stereb lives by calling in warnings from the planet's orbitalwatchstation and sending them to safety in Serroco's catacombs.[11] Life on Serroco did eventually continue, but irreparable damage had been done to the planet's surface[12]—furthermore, only eight of the ships grounded on the planet were able to make an escape.[3] One of them carried Jedi KnightMeetra Surik, who was one of a number of Jedi regularly assigned to the world.[16]

The loss of the Courageous threw some Republic planets, such as Telerath, into a panic,[17] and the "crime" of Serroco's destruction was immediately condemned by the Republic.[18] The Courageous itself was melted down for scrap by the Mandalorians, and part of it was fashioned into a battle-axe carried by Mandalore the Ultimate.[19] The memory of Serroco would become a rallying cry for the Republic going forward in the war. In transmissions aimed at the Mandalorians, Republic propagandist Benegryph Goodvalor named his imaginary warship the Serroco,[20] a name that would later be lent to a real Republic ship by the time of the Galactic War several centuries later.[21] "Goodvalor" was a Serroco survivor himself—he was Little Bivoli host Marn Hierogryph, who, along with the TrandoshancookSlyssk, had escaped the carnage in the nick of time by stealing a Republic troop transport, saving half a sleeping battalion in the process. For this, he was celebrated as the "Hero of Serroco", and the episode was turned into a propaganda story by the Republic Defense Ministry.[22] About a decade after the Battle of Serroco, during the Dark Wars,[6] a group of Republic veterans of the battle formed a gang in the Refugee Sector of the Smuggler's Moon, Nar Shaddaa.[12]